Class 7 | Understanding the Weather | Chapter 2| Social Science | Explanation | Animated Video · Study with fun
本视频讲解天气的形成与相关知识，包括大气层结构、天气现象及描述天气的五个要素。适合练习自然、科技、生活类词汇和表达。
Have you ever wondered why it is raining in one part of India while another place is bright and sunny?
你是否曾经好奇：为什么印度的某个地区正在下雨，而另一个地区却阳光明媚、万里无云呢？
Why do some places experience snowfall while others remain warm throughout the year?
为什么有些地方会下雪，而其他地方却全年都保持温暖呢？
These changes around us are called weather.
我们周围发生的这些变化被称为“天气”。
Weather is the condition or state of the Earth's atmosphere at a particular place and at a particular time.
天气是指地球大气在特定地点和特定时间下的状况或状态。
It keeps changing from hour to hour and from day to day.
它每小时、每天都在不断变化。
But what exactly is the atmosphere?
但是，大气究竟是什么呢？
The atmosphere is a blanket of gases surrounding our Earth.
大气层是由各种气体组成的“覆盖层”，它环绕着我们的地球。
We simply call this mixture of gases air.
我们 simply 将这种气体混合物称为“空气”。
Without it, life on Earth would not be possible.
没有它，地球上的生命就无法存在。
The atmosphere provides the air we breathe, protects us from harmful radiation,
大气层为我们提供了所需的空气，并保护我们免受有害辐射的侵害。
and helps maintain suitable temperatures for life.
并有助于维持适合生命存在的适宜温度。
Just like a cake, Earth's atmosphere has layers.
就像蛋糕一样，地球的大气层也分为不同的层次。
There are five main layers, from the ground to space.
从地面到太空，共有五个主要层次。
Each layer plays a very important role.
每一层都扮演着非常重要的角色。
As we move higher above Earth, we pass through different atmospheric layers.
当我们逐渐升高到离地球更远的地方时，会穿过不同的大气层。
In this chapter, we will focus mainly on the lowest layer called the troposphere.
在本章中，我们将主要关注最底层的大气层——对流层。
The troposphere is the lowest layer of the atmosphere.
对流层是大气层的最底层。
It is where humans, animals, and plants live.
这里是人类、动物和植物共同生活的场所。
Almost every type of weather occurs in this layer.
几乎所有类型的天气现象都可能在这个大气层中发生。
The troposphere extends from about 6 km near the poles to about 18 km near the tropical regions.
对流层从极地附近的大约6公里延伸到热带地区附近的大约18公里。
Cold air contracts, making the layer thinner, while warm air expands, making it thicker.
冷空气会收缩，从而使空气层变得更薄；而暖空气则会膨胀，从而使空气层变得更厚。
Clouds, rainfall, storms, snowfall, winds, and almost every weather phenomenon takes place inside the troposphere.
云层、降雨、风暴、降雪、风，以及几乎所有的天气现象，都发生在对流层内。
We use many words to describe the weather.
我们使用许多词语来描述天气。
Hot, cold, rainy, cloudy, windy, snowy, humid, and many more.
炎热、寒冷、下雨、多云、刮风、下雪、潮湿……还有许多其他天气状况。
Scientists describe weather using five important elements.
科学家们用五个重要的要素来描述天气状况。
These are temperature, precipitation, atmospheric pressure, wind, and humidity.
这些气象要素包括温度、降水量、大气压力、风速以及湿度。
Temperature tells us how hot or how cold the atmosphere is.
温度告诉我们大气层是热还是冷。
It changes throughout the day, depending on the sun's heating.
它在一天中的不同时间会发生变化，这取决于太阳的热量辐射。
Precipitation means any form of water that falls from the sky.
降水是指从天空降落的任何形式的水。
It may be rain, snow, sleet, or hail.
可能是雨、雪、雨夹雪，也可能是冰雹。
Although we cannot see it, the air around us has weight.
虽然我们看不见，但周围的空气是有一定重量的。
The force created by this weight is called atmospheric pressure.
这种重力所产生的作用力被称为“大气压力”。
Wind is the movement of air from regions of high pressure to regions of low pressure.
风是指空气从高压区域流向低压区域的运动现象。
Both its speed and direction are important.
它的速度和方向都很重要。
Humidity is the amount of water vapor present in the air.
湿度是指空气中水蒸气的含量。
Some places feel dry, while others feel moist and sticky because of higher humidity.
有些地方让人感觉干燥，而另一些地方则因为湿度较高而显得潮湿、黏腻。
No single element can describe the weather completely.
没有任何一个单一的因素能够完全描述天气状况。
Temperature, rainfall, air pressure, wind, and humidity all work together to create the weather we experience every day.
温度、降雨量、气压、风速以及湿度共同作用，形成了我们每天所经历的天气状况。
For thousands of years, people carefully observe nature to understand changes in the weather.
数千年来，人们一直仔细观察自然现象，以了解天气的变化。
Today, scientists use powerful instruments and satellites to make weather forecasts.
如今，科学家们利用先进的仪器和卫星来进行天气预报。